Kilian Vounckx (Nov 30 2025 at 21:28): Kilian Vounckx (Nov 30 2025 at 21:28):Like many others, I'm back for AOC after a while of not using roc. I'm going through Richard's gist:
app [main!] {
cli: platform "https://github.com/lukewilliamboswell/roc-platform-template-zig/releases/download/0.1-test/7iDKk44no3gF9Nrh2VyF8Y5yvy1jUBhrbhHURN1WQptB.tar.zst"
}
import cli.Stdout
main! = |_| {
Stdout.line!("Hello, World!")
Ok({})
}
I get the following error:
error: Failed to extract platform spec from app file: error.NotAppFile
Does anyone have the same issue? Or am I doing something wrong?
Luke Boswell (Nov 30 2025 at 21:31):Are you running roc built from source? zig build roc?
Kilian Vounckx (Nov 30 2025 at 21:32):No, latest release: Roc compiler version release-fast-77e8bbc1
Kilian Vounckx (Dec 01 2025 at 18:59):I just built from source: Roc compiler version debug-2ac12ee6. Still happening there unfortunately. What is weird is that it worked before. I then made some change (idk what exactly anymore) which would be a compiler error, but instead gave the error above. But after undoing the change, the above error stays. Is there some caching in place in a config or shared folder anywhere?
Anton (Dec 01 2025 at 19:06):On what OS are you?
Kilian Vounckx (Dec 01 2025 at 19:07):MacOS arm64
Anton (Dec 01 2025 at 19:12):I'm able to reproduce it
Kilian Vounckx (Dec 01 2025 at 19:16):Ah good first news! Not just my laptop being weird then. Hope the example helps with debugging the compiler!
In the meantime, do you have a workaround?
Anton (Dec 01 2025 at 19:17):Yes, use roc build from source (zig build roc) and this roc source code:
app [main!] { pf: platform "https://github.com/lukewilliamboswell/roc-platform-template-zig/releases/download/0.1-test/7iDKk44no3gF9Nrh2VyF8Y5yvy1jUBhrbhHURN1WQptB.tar.zst" }
import pf.Stdout
main! : List(Str) => Try({}, [Exit(I32)])
main! = |_args| {
Stdout.line!("Hello Roc!")
Ok({})
}
It seems like the header being multiline caused the issue
Kilian Vounckx (Dec 01 2025 at 19:21):Thanks for helping out!
Anton (Dec 01 2025 at 19:24):Kilian Vounckx said:
It seems like the header being multiline caused the issue
Can you make a github issue for that?
Kilian Vounckx (Dec 01 2025 at 19:27):Done!
Luke Boswell (Dec 01 2025 at 20:21):Is there some caching in place in a config or shared folder anywhere?
Yes, there is a roc cache -- when you first run an app, the roc cli links the pre-built host library from the platform with an interpreter shim into an executable and caches that. From then on whenever you "run" a roc app that uses the same platform you will be using a cached executable -- and just the Roc app parts will be recompiled and then interpreted.
Luke Boswell (Dec 01 2025 at 20:22):There is a --no-cache flag you can give roc to not use the cache and force a re-link of that interpreted host.
Yanni Papandreou (Dec 02 2025 at 22:54):Hi, I was also playing around with the the Roc compiler built from source (Roc compiler version debug-3df2aab6). I was following Richard's gist and tried this program:
app [main!] { pf: platform "https://github.com/lukewilliamboswell/roc-platform-template-zig/releases/download/0.1-test/7iDKk44no3gF9Nrh2VyF8Y5yvy1jUBhrbhHURN1WQptB.tar.zst" }
import pf.Stdout
import pf.Stdin
main! = |_args| {
Stdout.line!("What's your name?")
name = Stdin.line!()
Stdout.line!("Hello, ${name}!")
}
Doing so gave this:
-- TYPE MISMATCH ---------------------------------
This expression is used in an unexpected way:
┌─ main.roc:6:1
│
6 │ main! = |_args| {
│ ^^^^^
It has the type:
List(Str) => { }
But the type annotation says it should have the type:
List(Str) => Try({ }, [Exit(I32)])
Found 1 error(s) and 0 warning(s) for main.roc.
What's your name?
Yanni
Hello, Yanni!
Roc crashed: Error evaluating from shared memory: TypeMismatch
So I added Ok({}) at the end of main! and the error disappeared but I am now seeing this and I am not sure if its expected:
What's your name?
Yanni
Hello, Yanni!
error(gpa): memory address 0x105820000 leaked:
Unable to print stack trace: Unable to open debug info: MissingDebugInfo
(The status code is okay) - is this due to how I am building the compiler? Though I saw something similar with the release of the new compiler
Luke Boswell (Dec 02 2025 at 23:00):I suspect this is fixed in https://github.com/lukewilliamboswell/roc-platform-template-zig/pull/13
Luke Boswell (Dec 02 2025 at 23:00):That looks like a memory leak in the platform host
Luke Boswell (Dec 02 2025 at 23:01):If you are open to building the platform from source and testing to confirm, that would be amazing
Yanni Papandreou (Dec 02 2025 at 23:11):Happy to try this out - I'm a bit new to Roc so not sure the workflow for building a platform from source? I have cloned the roc repo and can build the compiler using the nix devshell. I see instructions here https://github.com/lukewilliamboswell/roc-platform-template-zig/tree/main for building the platform - I'm guessing I should get the latest from the PR branch, build then somehow use this in the program above instead?
Luke Boswell (Dec 02 2025 at 23:12):I just marged that PR so from main branch should be fine
Luke Boswell (Dec 02 2025 at 23:13):To build it just use zig build native -- zig build will also work but that will also build all the cross-compiled objects which you dont need
Richard Feldman (Dec 02 2025 at 23:13):I probably need to update that URL
Luke Boswell (Dec 02 2025 at 23:13):Then in your app you can use a relative path to the platform/main.roc file instead of a URL
Luke Boswell (Dec 02 2025 at 23:13):@Richard Feldman I haven't made a new build/release yet -- I can do that now
Yanni Papandreou (Dec 02 2025 at 23:16):@Luke Boswell thanks - will try now :)
Luke Boswell (Dec 02 2025 at 23:18):Give me 2secs I'll have a URL for you instead of needing to build from source
Luke Boswell (Dec 02 2025 at 23:20):Give this a try
app [main!] { pf: platform "https://github.com/lukewilliamboswell/roc-platform-template-zig/releases/download/0.2/2q3DaiQx3nYLwKbwwVbPrBeRhbxrWuYZxnPpYfJrdQJF.tar.zst" }
Thanks Luke, using that I see:
$ ./zig-out/bin/roc --no-cache main.roc
What's your name?
Yanni
Hello, Yanni!
error(gpa): memory address 0x103940000 leaked:
Unable to print stack trace: Unable to open debug info: MissingDebugInfo
error: Memory leak detected!
for reference this is the program:
app [main!] { pf: platform "https://github.com/lukewilliamboswell/roc-platform-template-zig/releases/download/0.2/2q3DaiQx3nYLwKbwwVbPrBeRhbxrWuYZxnPpYfJrdQJF.tar.zst" }
import pf.Stdout
import pf.Stdin
main! = |_args| {
Stdout.line!("What's your name?")
name = Stdin.line!()
Stdout.line!("Hello, ${name}!")
Ok({})
}
so the error message changed a bit and I get an status code of 1 instead of 0..
Luke Boswell (Dec 02 2025 at 23:25):ok great, I can reproduce the leak! I'll look into it
Yanni Papandreou (Dec 02 2025 at 23:26):thanks Luke!
Luke Boswell (Dec 02 2025 at 23:27):I'm in the middle of a big refactor rn, but should be able to look at it in a few hours
Yanni Papandreou (Dec 02 2025 at 23:33):Thanks, no rush at all!
Luke Boswell (Dec 03 2025 at 00:18):Yanni Papandreou said:
Thanks Luke, using that I see:
$ ./zig-out/bin/roc --no-cache main.roc What's your name? Yanni Hello, Yanni! error(gpa): memory address 0x103940000 leaked: Unable to print stack trace: Unable to open debug info: MissingDebugInfo error: Memory leak detected!for reference this is the program:
app [main!] { pf: platform "https://github.com/lukewilliamboswell/roc-platform-template-zig/releases/download/0.2/2q3DaiQx3nYLwKbwwVbPrBeRhbxrWuYZxnPpYfJrdQJF.tar.zst" } import pf.Stdout import pf.Stdin main! = |_args| { Stdout.line!("What's your name?") name = Stdin.line!() Stdout.line!("Hello, ${name}!") Ok({}) }so the error message changed a bit and I get an status code of 1 instead of 0..
New release with the fix for this
https://github.com/lukewilliamboswell/roc-platform-template-zig/releases/tag/0.3
@Richard Feldman if you wanted to update your URL in the notes
Richard Feldman (Dec 03 2025 at 01:18):thanks - url updated!
Last updated: Dec 21 2025 at 12:15 UTC